1. Field of the Invention
The invention relates to vehicles for loading trucks, railroad cars or the like. The invention also relates to material and article handling systems. More specifically, the invention is an air-bearing-supported unitized loading system.
2. Description of the Prior Art
The air bearing and its use for transporting loads on a thin film of air is well known in the prior art. Patents such as U.S. Pat. No. 3,826,329 to Crimmins et al. and U.S. Pat. No. 3,831,708 to Terry have described improved versions of the air bearing and attempted to devise train-like systems for moving cargo across a warehouse or across uneven terrain. Yet, the scope of these and other known structures using air bearings is limited to small scale loading as was previously reserved for lift trucks and hand carts. No structure has successfully applied air bearings to truly novel and previously unaccomplished tasks such as loading an entire railroad car or truck trailer with a single preassembled load.
While some air bearing structures allegedly can traverse an uneven floor surface, some surfaces are so uneven as to stop any known air bearing. For example, some refrigerated truck trailers have ribbed floors for allowing cool air to circulate around the load, and the gap between a warehouse dock and a truck to be loaded is often too wide for an air bearing to float over. Such nonuniform surfaces have prevented air bearings from replacing conventional wheel-supported loading means in many situations.
Loading cargo in trucks, railroad cars, and the like has always been a slow job that generally required numerous trips by a fork-lift bringing cargo to the vehicle and arranging the cargo for a compact load. Attempts to quicken the loading process have led to shipping truck trailers on railroad flat cars, but this system requires two vehicles to carry a single load. Thus, no satisfactory system is known for loading an entire truck or the like with cargo in a single rapid operation. The present invention solves the above problems of air bearings and unitized loading systems.